“If the legislature creates a new regulatory framework, P2H technology holds great potential for counteracting network bottlenecks whilst simultaneously making the most practical and efficient use of surplus electricity produced from renewables.”

Uwe Weber, Head of the Electricity and Heat Generation Division, Stadtwerke Lemgo GmbH

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P2H Lemgo: Germany’s first municipal power-to-heat plant

The Lemgo municipal utilities company (Stadtwerke Lemgo) covers 50 per cent of the city’s heat requirement through an extensive district heating network that includes combined heat and power (CHP) plants and large-scale thermal storage units. In 2012, the network was supplemented by Germany’s first power-to-heat plant operating in the public heat supply system, which was installed to store excess electricity from renewable energies in the form of heat.

The Lemgo municipal utilities company was quick to respond to the changing conditions in the electricity market and, as early as in 2010, it developed a concept for a power-to-heat (P2H) plant, because the available infrastructure (large-scale thermal storage units, use of CHP and existing heating network) provided ideal conditions for the introduction of P2H technology. With a capacity of five megawatts, the electric boiler then went into active operation in November 2012, becoming Germany’s first P2H plant in the public heat supply system.

Engine for progress:

Option for the storage of green surplus electricity

Opportunity to counteract network bottlenecks

Efficient and low-cost technology

Saving fossil energy sources

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Photo: Stadtwerke Lemgo

The power-to-heat plant, which went into operation in 2012, has a capacity of 5 megawatts and is integrated into the extensive district heating network that includes combined heat and power (CHP) plants and large-scale thermal storage units.

Storing green surplus electricity as heat

In connection with CHP-based district heating systems, power-to-heat represents a highly efficient, market-ready, cost-effective and uncomplicated technology enabling the sector coupling of power and heat. In 2015, around 5,000 gigawatt-hours of electricity from renewable energy sources were curtailed across Germany, because, especially on very windy days, the sluggish expansion of the power grids often resulted in network bottlenecks. Since the growth in wind and PV installations continues to be driven forward, it is safe to assume that such network bottlenecks will most likely continue to increase for the time being. In this case, P2H plants can ease the load on the power grids in network bottleneck situations by taking up the surplus electricity from renewable sources – which would otherwise be curtailed – and buffering it or making it available for use in the form of heat.

Sector coupling holds great potential – but there are impediments

P2H technology holds great potential for counteracting network bottlenecks whilst simultaneously making the most practical and efficient use of surplus electricity produced from renewables. The installation in Lemgo is therefore making a contribution towards achieving the energy transition and saving fossil primary energy in the process.

However, according to the project’s managers, the electricity market’s regulatory environment is currently preventing the plant from operating commercially. This is because the operators of P2H installations have to pay all of the levies placed on the purchase of electricity (such as electricity taxes, network charges and the renewable energy levy) themselves, even when the plants are offering flexibility functions that benefit the network – that is to say, providing important services for the stability of power grids. This led to corresponding adjustments being written into Germany’s Energy Industry Act in early 2017 and with it the first steps were taken towards the sector coupling of electricity and heat – however, the exceptions are thus far restricted only to those areas where the power grid is being further expanded, the so-called network bottleneck areas. To enable installations to operate on a sustainable and economically viable basis, and to promote the development of future-oriented technology, regulations specific to sector coupling will need to be written into law.

Photo: Stadtwerke Lemgo GmbH

“If the legislature creates a new regulatory framework, P2H technology holds great potential for counteracting network bottlenecks whilst simultaneously making the most practical and efficient use of surplus electricity produced from renewables.”

Uwe Weber, Head of the Electricity and Heat Generation Division, Stadtwerke Lemgo GmbH